A Display That Tracks Your Movements

A Display That Tracks Your Movements

Knockout: Multiple people can use this gesture-based interactive screen, called WAVEscape, developed by Samsung and Reactrix. Here, two people punch the air while playing a boxing game.

There could be a revolution brewing in billboard
advertising. Instead of simply presenting a static image, why not let people
interact with the advertisement? This is the vision of electronics giant
Samsung and interactive advertising company Reactrix
Systems. The two companies have partnered to bring 57-inch interactive
displays to Hilton hotel lobbies by the end of the year. These displays can “see”
people standing up to 15 feet away from the screen as they wave their hands to
play games, navigate menus, and use maps.

With the buzz surrounding the Wii, the iPhone, and
Microsoft’s Surface, “people are more open and ready to interact using their
hands and gestures,” says Matt Bell, chief scientist and founder of Reactrix. It’s
easy to see how a gesture-based
interface might work well for video games and virtual worlds, and certainly
companies such as Belgian startup Softkinetic
make systems for those very needs. But Reactrix is aiming for the out-of-home
advertising market, traditionally dominated by large static displays like
billboards. Founded in 2001, Reactrix has some experience already: today, its
interactive floor displays attract crowds in shopping centers across the
country.

The basic idea behind Reactrix’s system, and even low-end
gesture-based technologies such as the Sony PlayStation Eye, is to use a camera
to detect a person’s body, and then use computer vision algorithms to make
sense of the images. Reactrix and Softkinetic systems differ from the
PlayStation Eye, however, in that they record 3-D information as opposed to
just two-dimensional information. There are many types of cameras that
can capture 3-D scenes, says Bell,
but in its current models made with Samsung, the company is using a
stereoscopic camera with two lenses. Next to the camera is an infrared light
that projects an invisible pattern onto the people in front of the screen. Each
lens captures a slightly different view of what’s going on, and, based on the
disparity in the images, the system can distinguish distance down to a fraction
of an inch. Bell
adds that the projected light pattern helps the system’s accuracy in uneven
lighting.

When the camera collects the information, it automatically
dumps it into a specialized processor to analyze the depth data, bypassing
software that wouldn’t be able to compute fast enough. “Once that’s done, we
have a full-depth image showing the distance to every object,” Bell says. At this point,
Reactrix’s unique algorithms take over. One of the differentiating factors
between Softkinetic and Reactrix is that the former focuses on the detailed
motion of parts of a single body, whereas the latter strives to disambiguate
people and objects. Bell
doesn’t provide details, but he says that the code is designed to figure out
scenarios such as when people are holding hands, or if people are standing
shoulder to shoulder.